Drought in Utah, May 1 to 31, 2003

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
240 PM MDT WED APR 30 2003

W-E ORIENTED JET STREAK ALONG INTERSTATE-70 HAS DEFINED THE UNSTABLE
NORTH AND DRIER SOUTH. THE STREAK WILL WEAKEN TONIGHT BUT THE
FAVORED ETA STILL PRODUCES SOME 4-3 DIVERGENCE OVER NW COLORADO.
IN ADDITION...A VORT MAX OVER NV THIS AFTERNOON WILL PRODUCE LIFT
BEGINNING BEFORE MIDNIGHT TONIGHT. SO WILL KEEP SCATTERED TO
ISOLATED SHOWERS AND EVENING STORMS NORTH OF THE ROAN/TAVAPUTS
PLATEAU. COLD TEMPS IN THE MOUNTAINS TONIGHT WILL AGAIN LEAD TO
STRONG RH RECOVERY. THE SOUTH WILL HAVE THIN HIGH CLOUDS ONLY.

THURSDAY-THURSDAY NIGHT: SCATTERED ACTIVE WEATHER REMAINS ACROSS THE
NORTH. A SUBSIDENCE INVERSION WILL LIMIT CELL TOPS IN THE
AFTERNOON...BUT THE -20C ISOTHERM REMAINS IN THE UPDRAFT REGION SO
WILL MENTION AFTERNOON AND EARLY EVENING THUNDERSTORMS. SNOW LEVEL
REMAINS AROUND 7500 FEET WITH NO ACCUMULATION EXPECTED.  99/RAMEY

LONG TERM DISCUSSION:
FRIDAY AND SATURDAY: FLAT DIRTY RIDGE OVER THE FORECAST AREA ON
FRI AMPLIFIES OVER THE PLAINS STATES ON SAT AS WEST COAST TROUGH
MOVES INTO THE GREAT BASIN. MODELS IN FAIR AGREEMENT WITH TIMING OF
THIS FEATURE THROUGH SAT MORNING.  THEN THE GFS IS FASTER THAN THE EC
AS THE SHORTWAVE TRACKS ACROSS THE WESTERN CONUS INTO THE PLAINS SUN
THROUGH MON. 12Z ETA AND GFS SUPPORT FASTER TIMING. FOR THE DETAILS:
TEMPS CONTINUE TO WARM ON FRI. WILL KEEP A MENTION OF POSSIBLE
AFTERNOON MOUNTAIN THUNDERSTORMS OVER THE NORTH DUE TO AVAILABLE
MOISTURE THERE. THEN ON SAT LOOK FOR INCREASING INSTABILITY AND
SOUTHWEST WINDS AS THE SYSTEM APPROACHES. BOTH THE ETA AND GFS
INDICATE ONE VORT LOBE BRUSHING THE NORTH SAT AFTERNOON...AND 100+
KT JET ADDING UPPER LEVEL DIVERGENCE AS IT PUSHES INTO NORTHWEST NM.
COOLING ALOFT STARTS ON SAT WITH 500 MB TEMPS -20C BY 00Z SUN OVER
THE WESTERN HALF. MAIN LIMITING FACTOR TO AFTERNOON THUNDERSTORM
ACTIVITY WILL BE AMOUNT OF MOISTURE AHEAD OF THE TROUGH. WILL ADJUST
POPS UP A LITTLE AND EXPAND COVERAGE OF SLIGHT CHANCE TO SOUTHERN
MOUNTAINS.

SUNDAY: DIFFERENCES IN MODELS STILL LESS THAN IN PREVIOUS RUNS WITH
SUN PROMISING TO BE QUITE ACTIVE. BOTH SHOWING SPLIT FLOW REGIME
WITH SOUTHERN STREAM PUSHING OUT ACROSS THE DESERT SOUTHWEST ON SAT
NIGHT (GFS) OR SUN (EC). EVEN WITH THE FASTER GFS ANOTHER IMPULSE
DROPS ACROSS THE FORECAST AREA. THEREFORE CHANCE POPS LOOKS GOOD.
HEFFERNAN

MONDAY-WEDNESDAY: WRAP-AROUND MOISTURE TO AFFECT MUCH OF THE REGION
ON MONDAY AS STORM SYSTEM WRAPS UP OVER THE EASTERN PLAINS OF
COLORADO. BOTH EC AND GFS INDICATE A SECONDARY WAVE ON THE BACK-
SIDE OF THE SYSTEM TO ENHANCE SHOWERS AND THUNDERSTORMS. GFS
INDICATES BROAD BUT SHALLOW TROF OVER THE WESTERN U.S. TUESDAY INTO
WEDNESDAY. THEREFORE...WILL CONTINUE WITH CHANCE OR SLIGHT CHANCE
SHOWERS AND THUNDERSTORMS INTO MIDWEEK WITH COOLER THAN NORMAL
TEMPERATURES. NL

.GJT...NONE.

COZ001>014-017>023-UTZ022>025-027>029-011145-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
545 AM MDT WED APR 30 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN COLORADO AND FOR
EASTERN UTAH.

.DAY ONE...TODAY AND TONIGHT...

SCATTERED THUNDERSTORMS WILL OCCUR THIS AFTERNOON AND CONTINUE INTO
THE EVENING HOURS OVER THE NORTHERN MOUNTAINS AND NORTHERN VALLEYS.
ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS THE CENTRAL AND SOUTHERN
MOUNTAINS THIS AFTERNOON. LOCALLY STRONG GUSTS OF WIND WILL OCCUR
WITH SOME OF THE THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE THREAT OF ISOLATED THUNDERSTORMS WILL EXIST THURSDAY ACROSS THE
MOUNTAINS AND NORTHERN VALLEYS...AND CONTINUE ACROSS THE MOUNTAINS
FRIDAY AND SATURDAY. THE POSSIBILITY OF THUNDERSTORMS WILL INCREASE
SUNDAY THROUGH TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.